It has been known to use an auger or other cookie-cutter type tools to plant perennial flower bulbs, usually at between 4-6" deep. Cookie-cutter type tools are limited in what they do not pulverize the dirt, have no means to control multiple hole depths, require a lot of manual labor and are tough to use if there is a lot of debris on or in the soil.
Simple augurs are limited in what they do and are not designed for efficient use at the size and depth of pre-started annual flowers, which are the most common type of planting. Also, if a typical homeowner's variable speed drill is used to power an auger and is run slowly, it tends to bog down or grab. If it is run fast, the dirt flies all over the place and thus is not available to fill around the new plants. Also this flying debris can be a hazard to the gardener or others that may be nearby. If mulch or other types of ground cover are present, they contaminate the back-fill since the dirt coming out of the hole goes on top of this surrounding material. In addition there is no way to accurately and easily measure planting depth or provide for multiple planting depths. In some cases a rectangular tab has been welded on the shaft but this only gives a single depth, usually at 6" which is too deep for most perennials. This tab cannot be adjusted or go into the hole, and since it is spinning it can be dangerous.